7eyb | pdb_00007eyb
core proteins
Structural highlights
FunctionGP14_BPT7 Component of the cylindrical core that assembles on the inner surface of the capsid during capsid formation and plays a role in viral DNA ejection into the host cell. The inner core is composed of stacked rings of gp14, gp15 and gp16 proteins. Following binding to the host cell surface, the internal core is disassembled and gp14 is ejected along with gp15 and gp16 into the infected cell. May form a simple channel spanning the outer membrane.[HAMAP-Rule:MF_04118][1] Publication Abstract from PubMedMany tailed bacteriophages assemble ejection proteins and a portal-tail complex at a unique vertex of the capsid. The ejection proteins form a transenvelope channel extending the portal-tail channel for the delivery of genomic DNA in cell infection. Here, we report the structure of the mature bacteriophage T7, including the ejection proteins, as well as the structures of the full and empty T7 particles in complex with their cell receptor lipopolysaccharide. Our near-atomic-resolution reconstruction shows that the ejection proteins in the mature T7 assemble into a core, which comprises a fourfold gene product 16 (gp16) ring, an eightfold gp15 ring, and a putative eightfold gp14 ring. The gp15 and gp16 are mainly composed of helix bundles, and gp16 harbors a lytic transglycosylase domain for degrading the bacterial peptidoglycan layer. When interacting with the lipopolysaccharide, the T7 tail nozzle opens. Six copies of gp14 anchor to the tail nozzle, extending the nozzle across the lipopolysaccharide lipid bilayer. The structures of gp15 and gp16 in the mature T7 suggest that they should undergo remarkable conformational changes to form the transenvelope channel. Hydrophobic alpha-helices were observed in gp16 but not in gp15, suggesting that gp15 forms the channel in the hydrophilic periplasm and gp16 forms the channel in the cytoplasmic membrane. Structural changes in bacteriophage T7 upon receptor-induced genome ejection.,Chen W, Xiao H, Wang L, Wang X, Tan Z, Han Z, Li X, Yang F, Liu Z, Song J, Liu H, Cheng L Proc Natl Acad Sci U S A. 2021 Sep 14;118(37). pii: 2102003118. doi:, 10.1073/pnas.2102003118. PMID:34504014[2] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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